MHF4U UNIT 2.1: CHARACTERISTICS OF POLYNOMIAL FUNCTIONS Polynomial Function – A function whose equation is defined by a polynomial in one variable. The general equation is: 𝑓(𝑥) = 𝑎𝑛 𝑥 𝑛 + 𝑎𝑛−1 𝑥 𝑛−1 + 𝑎𝑛−2 𝑥 𝑛−2 + ⋯ + 𝑎2 𝑥 2 + 𝑎1 𝑥1 + 𝑎0 Degree of a Function – the value of the highest exponent of the variable Leading Coefficient – the coefficient of the term with the highest exponent Increasing – the graph rises going from left to right along the x-axis Decreasing – the graph falls going from left to right along the x-axis Turning Point – occurs where the function changes from increasing to decreasing or vice versa Local maximum/minimum – point where the function changes from increasing to decreasing/decreasing to increasing Local maximum/minimum value – y-coordinate of the local maximum/minimum Zeroes – a.k.a. roots, x-intercepts End Behaviour – The behavior of the y-values as x approaches positive infinity and as x approaches negative infinity Finite Differences – For a polynomial function of degree n, 𝑛𝜖Ζ+ , the nth differences are equal and have the same sign (+/-) as the leading coefficient. 1 MHF4U UNIT 2.1: CHARACTERISTICS OF POLYNOMIAL FUNCTIONS INVESTIGATING POLYNOMIAL FUNCTIONS Odd Degree Polynomial Functions Group A Graph y x3 y x3 x2 4x 4 y x3 5x2 3x 9 y x3 y x3 x2 4x 4 y x3 5x2 3x 9 End Behaviour # of Turning Points # of x-intercepts Group B Graph End Behaviour # of Turning Points # of x-intercepts Compare the graphs in Group A and B. How are they different? 2 MHF4U UNIT 2.1: CHARACTERISTICS OF POLYNOMIAL FUNCTIONS Even Degree Polynomial Functions Group A Graph y x4 y x4 x3 6x2 4x 8 y x4 3x3 3x2 11x 4 y x4 y x4 x3 6x2 4x 8 y x4 3x3 3x2 11x 4 End Behaviour # of Turning Points # of x-intercepts Group B Graph End Behavior # of Turning Points # of x-intercepts Compare the graphs in Group A and Group B. How are they different? 3 MHF4U UNIT 2.1: CHARACTERISTICS OF POLYNOMIAL FUNCTIONS SUMMARY Odd Degree Functions Type General Equation Degree of Polynomial Maximum Number of Roots Max Number of Turning Points Sketch Linear Cubic Quintic A polynomial of degree 7 is called a septic. 9 is called a nonic. End Behaviour 4 MHF4U UNIT 2.1: CHARACTERISTICS OF POLYNOMIAL FUNCTIONS Even Degree Functions Type General Equation Degree of Polynomial Maximum Number of Roots Max Number of Turning Points Sketch Quadratic Quartic Hexic (or sextic) A polynomial of degree 8 is called an octic. degree 10 is decic. End Behaviour 5